As is well known, wireless communication systems, such as Universal Mobile Telecommunication System (UMTS) and Long Term Evolution (LTE) systems, provide communication to mobile devices via a plurality of cells or serving areas, with each cell or area served by one or more base stations. The base stations are interconnected by a fixed network, which can communicate data between the base stations. A mobile device communicates via a radio communication link with a base station of the cell or serving area within which the mobile station is situated.
In order to extend coverage and capacity indoors, such as in residential or academic (e.g. university campus) or commercial or small business environments and especially where access would otherwise be limited or unavailable, systems with smaller sized cells served by small base stations, known as femtocells, have been developed. The third Generation Partnership Project (3GPP) refers to a UMTS femtocell that connects a 3GPP mobile device (referred to as User Equipment, UE) to a core network over UTRAN as a Home Node B (HNB). See for example, the 3GPP document TS 25.467 (UTRAN Architecture for 3G HNB), the disclosure of which is incorporated herein by reference. For LTE systems, 3GPP also refers to the femtocells as HeNBs. LTE HeNBs are part of an evolved UTRAN (EUTRAN) which connects UEs to a core network using, for example, a broadband IP backhaul.
With the increase in content available online, for example, via email, social networking sites, blogs, RSS feeds, multimedia voice-over-IP (VoIP) calls, streaming video and online music, and the availability of high-speed mobile broadband access technologies, such as LTE, there has been a significant increase in demand by users for Internet data access. Increased demand in a network impacts the network's available bandwidth and capacity.
In order to efficiently provide access to local IP networks and to offload data traffic from macro networks (thus, increase network capacity too), operators have introduced Local IP Access (LIPA) into their networks which enables IP-enabled UEs to access a consumer's residential or home-based local network (e.g. so that IP traffic generated via the HeNB is routed directly to the users local network) as well as the broader Internet directly using the air interface of a femtocell, for example a HeNB. Using LIPA facilitates the offloading of traffic from the operator's core network which is ultimately destined for the Internet and also provides access to the devices connected in the residential or home-based local network (e.g. desktop/laptop computers, printers, Internet-enabled gaming systems, media centres).
3GPP has defined a solution for providing LIPA in a residential or home-based environment in TS 23.401 and TS 23.060, the disclosures of which are incorporated herein by reference. The 3GPP solution is based on a local gateway (which provides access to the local network) collocated in a femtocell, HeNB or HNB.
3GPP is currently looking at solutions for deploying LIPA in enterprises or enterprise environments, where enterprises may include corporations, small businesses, non-profit institutions, government bodies, academic campus' or similar enterprise environments. In enterprise deployment, the coverage area is larger than a residential deployment and so a plurality of femtocells (HeNBs or HNBs) are required to provide connectivity to the local network in the enterprise. However with a plurality of femtocells in an enterprise, as a user connected to a femtocell moves beyond coverage of the femtocell but still within the enterprise, the user will loose connectivity to the local network. In view of the impact to a user, not providing continuity to LIPA beyond a femtocell is a significant drawback when deploying LIPA in enterprise environments.
Two solutions have been proposed to 3GPP for deploying LIPA in enterprise environments.
The first solution proposes using a new interface Sxx between HeNB and a local gateway (LGW) to the local network. Two versions of the new interface Sxx have been proposed. In 3GPP Tdoc written contribution meeting document S2-102432, the disclosure of which is incorporated herein by reference, it has been proposed that Sxx is a User Plane (UP) only interface and in 3GPP Tdoc written contribution meeting document S2-102433, the disclosure of which is incorporated herein by reference, it has been proposed that Sxx is a User Plane (UP) and a Control Plane (CP) interface. Both versions of this solution however require a new interface and mobility mechanism to be specified and also requires the HeNB to support GPRS Tunnelling Protocol-Control (GTP-C). Thus, this solution is complex to implement and requires significant changes to the existing architecture.
The second solution proposes moving the Serving Gateway (SGW) from the core network to the enterprise and was proposed in 3GPP Tdoc written contribution meeting document S2-102180, the disclosure of which is incorporated herein by reference. This solution requires that a SGW relocation is performed every time the UE moves into or out of the enterprise area and also means that the SGW, which includes functionality such as operator charging and charging interfaces, must be moved into the enterprise. Thus, this solution requires changes to the existing architecture and additional signalling when the UE moves into or out of the enterprise area.